1. Field of the Invention
The present invention is directed to wellbore operations, in-tubing sidetracking operations, wellbore milling procedures, and apparatuses and systems useful in such operations and procedures.
2. Description of Related Art
Many completed wells have one or more strings of tubing extending within casing from the surface (or from a tubing hanger) down within the well to a location above completion apparatus in a completion zone. Typically the interface at the lower end of the tubing string and the interior of well casing is sealed, e.g. with a packer or other sealing device. It is also common for a travel joint between the packer and tubing end to accommodate relative movement between the two.
Often it is desirable to produce the well from alternate zones, including, but not limited to, a location above the packer at the end of the tubing string. In several prior art methods, the tubing string is removed to accomplish a sidetracking operation above the level of the original completion zone. Once the tubing is removed a new annulus or primary barrier is installed above a new tubing-casing exit from which a new lateral wellbore extends.
In various prior art methods, new exits (exit openings through tubing, cement and casing) have been provided, an new lateral wellbores drilled therefrom, with the exits positioned below an existing annulus barrier. Such exits and lateral wellbores have been established using coiled tubing without requiring the use of a rig above the wellbore.
Often it is desirable to move up above a current completion zone due to, e.g., offset distance of a new drainage target which requires a well path beginning at a higher point in the wellbore due to maximum build angles versus the distance a well can be drilled due to friction of pipes pushed around curves in the wellbore.
There has long been a need for an efficient and effective method for re-completing a well in tubing above a previous completion location. There has long been a need for a method that efficiently and effectively provides a suitable opening or window through tubing and casing for drilling a sidetracked lateral wellbore at a desired re-completion location. There has long been a need, recognized by the present inventors, for stabilizing tubing at the desired re-completion location. There has long been a need for such a system and method wherein a new primary barrier is provided without the need to remove an entire tubing string.
The present invention, in certain aspects, provides a method for wellbore operations in an earth wellbore with tubing within casing in an earth wellbore, the wellbore extending down into earth from an earth surface, the tubing comprising a tubing string with a lower end and extending down within the casing with the lower end at a point above a lower end of the casing, a tubing-casing annulus between the tubing and the casing sealed by a first sealing apparatus, the method including sealing the lower end of the tubing string with a sealing device to prevent fluid flow therethrough, and sealing the tubing-casing annulus with a second sealing apparatus above and spaced apart from the first sealing apparatus.
The present invention, in certain embodiments, discloses a through-tubing in-tubing system for providing a tubing/casing exit above a first completion zone in a main wellbore for drilling a new lateral wellbore from the main wellbore. In one embodiment in which a tubing-casing annulus is initially sealed off at a lower end for production below the tubing, another seal is provided within the tubing-casing annulus above and spaced apart from the lower seal. Then the tubing is perforated between the two seal areas, preferably without perforating the casing. In one aspect a travel joint, (including, but not limited to, a commercially available ELTSR receptacle from Baker Oil Tools) part of which encompasses the lower end of the tubing, is also perforated. Cement, resin or other suitable hardenable material is then pumped from the surface, down the interior of the tubing string, out through the perforations, and up into the annulus between the tubing""s exterior and the casing""s interior to such a level to stabilize a portion of the tubing for making one or more exit openings in the tubing and casing below that cement level.
The exit opening(s) are made with any suitable known apparatuses, equipment and methods, including, but not limited to, with a mill or mills, jet cutter(s), and explosives. In certain aspects, a diverter, mill guide, and/or whipstock is positioned and secured for directing a mill or mills against the tubing and/or casing. A suitable mill or mills are then used to make the exit opening(s) or window(s). In one aspect the mill or mills are run on a string rotatable from the surface. In another aspect, a coiled tubing string is used that includes a downhole motor for rotating a mill. Such a coiled tubing string may be used within the tubing that does not necessitate removal of the tubing string from the well or removal of a wellhead at the surface. The emplacement of the seal apparatus and perforating of the tubing can also be done without removal of the wellhead.
Once the exit opening(s) are provided, a lateral wellbore may be drilled out (xe2x80x9csidetrackedxe2x80x9d) from the casing exit as desired. The lateral wellbore may then be lined or cased as is well known in the art.
In another embodiment, following sealing of the tubing, cementing, and sidetracking, a jet cutter is lowered into the tubing to sever the tubing above the sealing apparatus. The entire tubing string is then raised at the surface and re-hung to provide a desired gap, e.g. of 30 feet in length, at a desired location down in the wellbore for installing a new upper primary barrier.
In yet another embodiment, following sealing of the tubing, cementing, and sidetracking as described above, an explosive device according to the present invention is run into the tubing and positioned adjacent the area at which a tubing gap is desired. One or more selectively activatable holding subs, e.g. but not limited to, the xe2x80x9cbutton subsxe2x80x9d or xe2x80x9chold downsxe2x80x9d disclosed in U.S. Pat. No. 5,785,120, are activated by pumping fluid under pressure down the tubing string to secure the explosive device in position. Alternatively mechanical anchors or the like may be used. A fluid pressure-activated firing head of the explosive device is activated by pumping fluid under pressure down the tubing string. The firing head simultaneously fires three separate charges: 1. a top charge that severs the tubing at a top level; 2. a bottom charge that severs the tubing at a bottom level; and 3. a slotting charge that fires to produce a series of longitudinal slots and corresponding fingers in and around the severed tubing. The explosive device is connected at the end of a tubing or coiled tubing string which is then lowered, pushing the housing of the explosive device down into the remaining tubing. The button sub(s) hold the severed tubing and, as the severed tubing is lowered, the fingers go down between the tubing""s exterior and the casing""s interior, creating an open axial gap in the tubing. The button sub(s) are then released and the housing of the explosive device is retrieved from the tubing. A sealing apparatus, e.g. an inflatable packer or, a mechanical packer, either of which may be a through-tubing packer or, is then run into the tubing on a tubing string or on coiled tubing and positioned at the gap in the tubing. Activating the packer seals off the tubing/casing annulus. The string is then released from the packer and retrieved from the wellbore.
In another embodiment a system with a mill and a downhole motor on coiled tubing is positioned with a mill adjacent the desired location for removal of a section of the tubing. The system is secured in place within the tubing with any suitable securement apparatus, including, but not limited to, one or more of the button subs discussed above. The system also includes a movement or stroking apparatus, e.g., but not limited to, as disclosed in FIGS. 1A-1E of U.S. Pat. No. 5,785,120 and accompanying text or in U.S. application Ser. No. 09/183,943 filed Oct. 31, 1998. The coiled tubing string includes a downhole motor that rotates the mill as the stroking apparatus pulls the coiled tubing and, hence, the mill upwardly to mill out the desired gap in the tubing. Depending on the length of the stroke of the stroking apparatus and the length of a desired milled gap in the tubing, more than one stroke may be needed. Alternatively any known milling or cutting system and method, including those in which a mill mills downwardly upwardly, or both and is supported from the surface and/or within the tubing below the surface may be used.
In any method described herein the stabilization and/or perforating and cementing steps may be optional. It is also to be understood that whenever a sealing apparatus is mentioned it may, within the scope of this invention, be any known suitable inflatable or mechanical packer (including but not limited to hydraulically set packers, mechanically set packers, and hydraulically set mechanical packers).
It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:
New, useful, unique, efficient, and novel and nonobvious methods for re-completing a well above a previous completion zone;
Such methods which do not require removal of a wellhead and related equipment from a wellbore;
Such methods which provide a new primary barrier around a tubing string above a new completion zone;
Such methods which do not require re-installation of a drilling rig;
Such methods which employ stabilization of a portion of tubing in a wellbore prior to making a tubing exit through that tubing portion;
Such methods which do not require the removal of a tubing string to provide a new exit above a previous completion zone in an area through which a tubing string extends; and
Apparatus and equipment useful in such methods.
Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures and functions. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one skilled in this art who has the benefits of this invention""s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent""s object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.